Generally, mobile communication systems have been developed to provide communication while ensuring user mobility. With continuing technological development, a mobile communication system is now able to provide a high-speed data communication service as well as a voice communication service. The wireless communication system includes base stations which provide a service within a predefined geographical area, which is called a “cell”. In order to ensure the user's mobility, when the user gets out of the cell due to his/her movement, a handover between cells is performed. Furthermore, inter-Radio Access Technology (RAT) change may be supported.
In order to support the handover and the inter-RAT change, there is a need for information about other cells or other RATs to which a terminal may connect in a current situation. That is, the terminal is required to perform measurement with respect to other cells and other RATs besides a serving cell or a serving RAT. In a 3rd Generation Partnership Project (3GPP) Long Term Evolution (LTE) system which has emerged as a next generation mobile communication system, the terminal performs the measurement by using a measurement gap. The measurement gap is illustrated in FIG. 1.
FIG. 1 illustrates an example of a measurement gap in a wireless communication system according to the related art. FIG. 1 illustrates a resources usage state. Referring to FIG. 1, the majority of resources is used for service intervals, that is, are used to transmit and receive the data and control information of base stations and terminals. In this case, a measurement gap 110 is located in some intervals. In an LTE system, the measurement gap 110 may be 6 ms long per 40 ms or 80 ms time period. During the interval of the measurement gap 110, a base station does not perform scheduling for a relevant terminal. In order words, during the interval of the measurement gap 110, the base station does not perform communication with the relevant terminal. Accordingly, the terminal performs measurement with respect to at least one of the frequency of a serving cell, another frequency and another RAT during the measurement gap 110.
While performing the measurement, the terminal may not be provided with a service. Therefore, the interval for the measurement may be assigned restrictively. In this case, since a change of settings in the RF module of the terminal and a stabilization time are required for the measurement, there is a limitation in the performance of an implementation including hardware when measurement is performed for a given time interval. Therefore, satisfied measurement results may not be obtained according to a channel situation, so that an optimal cell or RAT may not be selected.
The above information is presented as background information only to assist with an understanding of the present disclosure. No determination has been made, and no assertion is made, as to whether any of the above might be applicable as prior art with regard to the present disclosure.